“Today’s System is tomorrow’s IC”. Let’s learn about IC test history and how it
can help System Test
Reviewing IC test history can help to understand where
PCB and System Test methodologies are today and the direction they will go in the future. The dates that will be
shown are just generalizations on the industry,
some companies will have different time lines.
1970s to Mid-1980s
Functional Test dominated digital IC test methods.
However, increasing functional test development times
and decreasing stuck-at fault coverage drove development of internal scan
chains that were inserted in the IC design.
Internal scan enabled ATPG (Automatic Test Pattern Generation) tools to generate
test patterns for high stuck-at fault coverage.
Many companies/vendors using ‘ad-hoc’
approaches and non-structured DFsT such as ‘partial scan’.
At-Speed tests were normally
performed with Functional Test. Some companies (HP, IBM) have advanced methods for at-speed
tests using path-delay
tests
Late 90s-2000 – All companies using
‘partial scan’ gone. All digital IC test include structural scan-based test for
stuck-ats. Scan infrastructure in IC is
standard. BIST
2000-Present – Test times (due to IC density) and capital
equipment costs have driven embedded IC test
(BIST). IC functional speeds surpass speed of ATE, hence on-board or scan-based
at-speed structural test is adopted by many
companies
Beyond - More
standardization on at-speed structural test either embedded or executed with low cost/low speed tester. Noise, crosstalk,
signal integrity test problems need to be solved. Standards
such as P1500 enable test re-use, so test vectors follow building blocks.